[01] Kuldeep Pareta, DHI (India) Water & Environment Pvt Ltd, New Delhi, India. [02] Flemming Jakobsen, DHI (India) Water & Environment Pvt Ltd, New Delhi, India. [03] Madhu Joshi, Risk Management Solutions (RMS), Noida, Uttar Pradesh, India.

The torrential rains in June 2013 combined with melting of snow caused voluminous floods in the rivers of Uttarakhand and subsequently triggered widespread mud, landslides and debris deposition. The event caused instability of the channel by shifting the banks. The main hazards in region related to the rivers are flooding, landslide, soil erosion, and river bank instability. Criteria to identify the vulnerable reaches are based on risk, exposure and hazards in that area. The magnitude of risks due to flood hazards on various exposures along the riverbank is calculated based on qualitatively derived scores. Erosion rendered many locations along the banks vulnerable to economic and human loss. The extent and magnitude of risks have been assessed based on information of past events, rapid field assessments, current mitigation measures and interactions with the locals. The findings from these interactions, and secondary data based on geospatial analysis of bank line changes have been used in the identification of vulnerable reaches of the rivers. The shifts in reaches are calculated by digitizing the bank line using satellite imageries of year 2005, 2010 and 2015. Susceptibility of banks and damages by high discharge along bank line are also studied. A fuller understanding will enable decision makers towards more efficient resources management for prevention and mitigation of flood events.

Vulnerability, Landslide, Flood, Bankline Changes, Himalaya, Disaster, Extreme Rainfall

[01] Nadim, F., Kjekstad, O., Peduzzi, P., Herold, C., and Jaedicke, C. (2006). Global landslide and avalanche hotspots. Landslides, 3: 159-173. [02] Bajracharya, S. R., and Mool, P. (2009). Glaciers, glacial lakes and glacial lake outburst floods in the Mount Everest region, Nepal. Annals of Glaciology, 50 (53): 81-86. [03] Immerzeel, W. W., Beek, L. P. H., and Bierkens, M. F. P. (2010). Climate change will affect the Asian water towers. Science, 328. [04] Petley, D. (2012). Global patterns of loss of life from landslides. Geology, 40 (10): 927-930. [05] Dobhal, D. P., Gupta, A. K., Mehta, M., and Khandelwal, D. D. (2013). Kedarnath disaster: facts and plausible causes. Current Science, 105 (2): 171-174. [06] Allen, S. K., Rastner, P., Arora, M., Huggel, C., and Stoffel, M. (2016). Lake outburst and debris flow disaster at Kedarnath, June 2013: hydrometeorological triggering and topographic predisposition. Landslides, 13 (6): 1479-1491. [07] Guha-Sapir, D., Below, R., and Hoyois, P. (2014). EM-DAT: International Disaster Database. Université Catholique de Louvain, Brussels, Belgium. [08] Sati, S. P., and Gahalaut, V. K., (2013). The fury of the floods in the north-west Himalayan region: the Kedarnath tragedy. Geomatics, Natural Hazards Risk, 4: 193-201. [09] Martha, T. R., Roy, P., Govindharaj, K. B., Kumar, K. V., Diwakar, P. G., and Dadhwal, V. K. (2014). Landslides triggered by the June 2013 extreme rainfall event in parts of Uttarakhand state. India Landslides, 12 (1): 135-146. [10] ICIMOD. (2011). Glacial lakes and glacial lake outburst floods in Nepal. International Centre for Integrated Mountain Development (ICIMOD), Kathmandu. [11] Clague, J. J., and Evans, S. G. (2000). A review of catastrophic drainage of moraine-dammed lakes in British Columbia. Quaternary Science Reviews, 19: 1763-1783. [12] O’Connor, J. E., Hardison, J. H., and Costa, J. E. (2001). Debris flows from failures of Neoglacial-age moraine dams in the three sisters and mount Jefferson wilderness areas, Oregon. US Geological Survey Professional Paper, 1606. [13] Worni, R., Huggel, C., and Stoffel, M. 2013. Glacier lakes in the Indian Himalayas from an area-wide glacial lake inventory to on-site and modelling based risk assessment of critical glacial lakes. Science of the Total Environment, 468-469. [14] Pranab, K. D. (2013). The Himalayan tsunami - cloudburst, flash flood & death toll: a geographical post-mortem. Journal of Environmental Science, Toxicology and Food Technology, 7 (2): 33-45. [15] Dobhal, D. P., Mehta, M., and Srivastava, S. K. (2013). Influence of debris cover on terminus retreat and mass changes of Chorabari glacier, Garhwal region, central Himalaya, India. Journal of Glaciology, 59 (217): 961-971. [16] Rao Durga, K. H. V., Rao, V. V., Dadhwal, V. K., and Diwakar, P. G. (2014). Kedarnath flash floods: a hydrological and hydraulic simulation study. Current Science, 106 (4): 598-603. [17] Ravi, S., Sorabh, G., Swapneel, K., and Lalit, K. (2017). Geotechnical Investigation across a failed hill Slope in Uttarakhand - a case study. Indian Geotechnical Conference 2017 GeoNEst 14-16 December 2017, IIT Guwahati, India. [18] Bhambri, R., Mehta, M., Dobhal, D. P., Gupta, A. K., Pratap, B., Kesarwani, K., and Verma, A. (2015). Devastation in the Kedarnath (Mandakini) valley, Garhwal Himalaya, during 16-17 June 2013: A remote sensing and ground-based assessment. Natural Hazards, 80 (3): 1801-1822. [19] Cho, C., Li, R., Wang, S. Y., Yoon, J. H., and Gillies, R. R. (2016). Anthropogenic footprint of climate change in the June 2013 Northern India Flood. Climate Dynamics, (46) 3: 797-805. [20] Bhatt, G. D., Sinha, K., Deka, P. K., and Kumar, A. (2014). Flood hazard and risk assessment in Chamoli district, Uttarakhand using satellite remote sensing and GIS techniques. International Journal of Innovative Research in Science Engineering and Technology, 3 (8): 15348-15356. [21] Vishwanath, V. H., and Tomaszewski, B. (2018). Flood hazard, vulnerability and risk assessments for Uttarakhand state in India. Geospatial Technologies and Geographic Information Science for Crisis Management (GIS) Proceedings of the 15th ISCRAM Conference - Rochester, NY, USA May 2018. [22] Pareta, K., and Pareta, U. (2011) a. Developing a national database framework for natural disaster risk management. In: ESRI International User Conference, San Diego, California, 2011. [23] AHEC/IITR Report. (2011). Assessment of cumulative impact of hydropower project in Alaknanda and Bhagirathi Basin. MoEF, GOI, New Delhi. [24] Vohra, Y. K., Olijnik, H., Grosshans, W., and Holzapfel, W. B. (1981). Structural phase transitions in Yttrium under pressure. Physical Review Letters, 47 (15): 1065. [25] Dube, A., Ashrit, R., Ashish, A., Sharma, K., Iyengar, G. R., Rajagopal, E. N., and Basu, S. (2013). Forecasting the heavy rainfall during Himalayan flooding - June 2013. Weather and Climate Extremes, 4: 22-34. [26] Auden, J. B. (1934). The Geology of the Krol Belt. Bulletin Geological Survey of India, 67 (4): 357-454. [27] Gansser, A. (1964). Geology of the Himalayas. Wiley Inter-Science, New York, 289. [28] Verma, R. K., Hamza. V. M., and Panda, P. K., (1970). Further study of the correlation of heat flow with age of basement rocks. Tectonophysics, 10: 301. [29] Krishnaswamy, V. S., and Ravi S. (1982). Scope of Development, exploration and preliminary assessment of the geothermal resource potential of India. Geological Survey of India (GSI), 111 (2): 17-40. [30] Dhingra, D., and Chakrapani, G. J., (2004). Estimation of silicate weathering in upper Ganga river in Himalayas, India. Himalayan Geology, 25 (2): 139-144. [31] Celerier, J., Mark Harrison, T., Beyssac, O., Herman, F., Dunlap, J. W., and Alexander, W. A (2009). The Kumaun and Garwhal Lesser Himalaya, India: Part 2. Thermal and deformation histories. Geological Society of America Bulletin, 121 (9-10): 1281-1297. [32] Pareta, K., and Joshi, M. (2018). Natural hazards, vulnerability and prevention of natural disasters in middle Himalaya, Uttarakhand. In: 19^th ESRI India User Conference, 2018. [33] Pareta, K., and Pareta, U. (2013). Geological investigation of Rahatgarh waterfall of Sagar (M. P.) through the field survey and satellite remote sensing techniques. International Journal of Geology, 5 (3): 72-79. [34] Pareta, K., and Pareta, U. (2016). Landform classification and geomorphological mapping of Ramgarh structure, Rajasthan (India) through remote sensing and geographic information system (GIS). Journal of Hydrology and Environment Research, 4 (1): 1-17. [35] Fujita, K., Sakai, A., Takenaka, S., Nuimura, T., Surazakov, A. B., Sawagaki, T., and Yamanokuchi, T. (2013). Potential flood volume of Himalayan glacial lakes. Natural Hazards and Earth System Sciences (NHESS), 13: 1827-1839. [36] Pareta, K., Kumar, J., and Pareta, U. (2012). Landslide hazard zonation using quantitative methods in GIS. International Journal of Geosciences and Geo-Information Technology (IJGGT), 1 (1): 1-9. [37] Pareta, K., and Pareta, U. (2011) b. Quantitative morphometric analysis of a watershed of Yamuna basin, India using ASTER (DEM) data and GIS. International Journal of Geomatics and Geosciences, 2 (1): 248-269.